There are two general approaches in analyzing fluid mechanics problems:
- Eulerian method: Fluid motion is described by fluid properties at different locations and times, using at fixed locations.
- Lagrangian method: Fluid motion is described by properties of fluid particles at different times, following individual fluid particles as they move about, using .
The two methods are equivalent in terms of fluid motion description. In practical applications, the Eulerian method is more popular. In some cases, Lagrangian method can be very simple.